Do you remember Tribes, Nina Raine's play about deaf seclusion? It played a month's run at the Royal Court back in 2010 but, despite some speculation about a potential West End run, that was the last we saw of it.

Raine's play has, however, been a huge international success. It has been seen in 15 different countries – three times as many as War Horse – and in some cases had multiple productions. The US has already run 14 different professional productions, with another 10 lined up. By the end of 2014 it will have had more professional productions outside the UK than its British premiere had performances.

Tribes is not alone in its extensive international life. Duncan Macmillan's Lungs has been Lunger, Longen, Pulmons and Atmen (Danish, Dutch, Spanish and German) in some of its 15-odd productions since 2011, and there are several more en route. Nick Payne's Constellations – also a two-hander – has proved another strong traveller, although it's still awaiting a US premiere.

Britain is, and has always been, very good at exporting plays. "If you're sitting anywhere else on planet earth, you know that this country is the country that produces plays," says director Ramin Gray, a former international associate at the Royal Court. "Wherever you are, you'll see more British plays than anything else – apart from maybe Neil Simon. On the whole, British plays have a better build quality."

What's curious though is that we rarely hear of such successes. Invariably, when we talk of British theatre overseas, we mean productions. War Horse, Matilda, Les Misérables: production franchises, global brands. Otherwise we might refer to smaller touring operations, such as 1927 or The Strange Undoing of Prudencia Hart. We don't generally think of British plays revived by local creative teams as a British success story.

When culture secretary Maria Miller stressed the importance of cultural exports at the British Museum last April, she name-checked War Horse, Matilda, Shakespeare's Globe and the Birmingham Royal Ballet. "British culture is perhaps the most powerful and compelling product we have available to us," she said.

Miller stressed the need to make the economic case that day, so why aren't Britain's new writing organisations shouting about their international reach? In Battalions, Fin Kennedy's survey designed to present a case for the sector, makes little mention of it.

Bureau de change

International revivals can be remarkably lucrative. Rights for a single territory can fetch between £2,000 and £10,000, depending on the size of the theatre and nature of the production, with premieres at the top end. That makes it quite possible for a playwright to earn a six-figure sum off the back of a single play.

It's that, says Raine, which can make being a playwright "completely viable". Commissioning fees are not particularly lucrative in theatre and a playwright would need several major commissions a year for a reasonable salary. Instead it is royalties and rights that pay dividends over time – sometimes more so than television.

"The money in TV is better to begin with," says Raine. "But the slow-burn of plays is such that it can earn you enough money that you don't continually have to write TV treatments for the quick buck. You write a play and it carries on earning."

Her debut, Rabbit, which premiered at the Old Red Lion in 2006 after three years of rejection letters, still gets professional productions around the world eight years on. "You write this play and put it on in a pub theatre and, eventually, it earns you more money than you've ever earned writing TV. You wouldn't think that would be the case, but it actually is."

Of course, only a small percentage of plays get international productions and fewer still are revived regularly enough to create a reliable income stream. Macmillan admits that he "wouldn't be able to live off the income of international productions of Lungs". But the old adage that says you can't make a living from theatre, only a killing, holds true to some extent. Think how regularly a modern classic like The Weir has been revived globally since its 1997 premiere.

A new frontier

The difficulty is that it's just not possible to predict which plays will go global. Debbie Isitt's marital comedy, The Woman Who Cooked Her Husband, is usually on stage somewhere, while Marie Jones's Stones In His Pockets is an unlikely Scandinavian favourite.

That leaves venues unable to bank on such income. As the Royal Court's executive director Lucy Davies explains: "We get participation in future royalties, but only when the writer has reached a certain threshold within a certain window of time. We certainly don't budget for it and we don't expect it."

That's despite Royal Court plays having had 70 productions around the world in the past three years alone. "The work isn't a massive income stream for us, but it's brilliant for our reputation," adds Davies. Plus, if it's good for the Royal Court's playwrights, it's good for the Royal Court.

There has always, as Gray says, been interest in British plays, but it's fair to say that the international marketplace has expanded in a few ways. First, we're seeing an increase in international collaborations. New territories have opened up – China, Singapore, Malaysia – but the speed of turnaround has also drastically increased. The internet has also made it easier to stay connected to far-off theatre locales and their critical and commercial hits. An increasingly connected global society has also meant that plays can become more universal in their concerns.